Comparative experimental studies of high-temperature mechanical properties of HSSs Q460D and Q690D

The test data for both 460 MPa and 690 MPa steels commonly show discreteness in their high-temperature mechanical properties. In this study, a comparative experimental investigation was conducted on Q460D and Q690D steels at temperatures ranging from 20 °C to 900 °C using concordant test conditions, which eliminated the discreteness induced by different test conditions. The results showed that the differences in the reduction factors for the f 1.0 , f 1.5 , and f 2.0 yield strengths between the Q460D and Q690D steels were negligible. A comparison of the test results with current standards and the available results showed that the difference between the 460 MPa and 690 MPa steels decreased significantly after excluding the effects of the test conditions. In addition, the f 1.0 yield strength, as recommended by GB51249, was applicable to both the Q460D and Q690D steels, as were the f 1.0 and f 1.5 values recommended by BS5950, and the f 2.0 values recommended by EC3 and AISC. Moreover, predictive equations were proposed for calculating the reduction factors of the mechanical properties of the Q460D and Q690D steels at elevated temperatures. The mechanical properties of HSSs Q460D and Q690D at temperatures ranged from 20 °C to 900 °C were comparatively investigated with concordant test condition. The test results were compared with the current mainstream standards and available results in literatures. For the reduction factors of yield strength f 1.0 , f 1.5 and f 2.0 at elevated temperatures, the differences between Q460D and Q690D steels are negligible. The dispersion of test data of 460 MPa and 690 MPa steels could be efficiently reduced by adopting concordant test condition. Equations for calculating the reduction factors of mechanical properties of Q460D and Q690D steels at elevated temperatures were proposed. • Comparative tests were conducted on Q460D and Q690D steels at elevated temperatures. • Test results were compared with the mainstream standards and available test data. • Differences on reduction factors of f 1.0 , f 1.5 and f 2.0 between Q460D and Q690D steels are negligible. • Difference between 460 MPa and 690 MPa steels decreased significantly after excluding the effects of the test conditions. • Predictive equations were proposed for calculating the reduction factors.